The invention relates to a planner device for planning a route through a topological road network, comprising:
background memory means for storing said network as a set of n-cell tables (n=0, 1) of road segments or junctions;
random access working memory means coupled to the background memory means, for storing a subset of said set of n-cell tables as actually used in said planning address assigning means for assigning a first working memory address to each entry of each n-cell table used in planning the route; data processing means coupled to said working memory means comprising:
expansion means for pointing to a set of candidate n-cells for said route, starting from one end of the route until the other end of the route is reached, on the basis of an actual expansion index indicating an actual n-cell;
evaluation means for assigning an evaluation value to each candidate n-cell found;
selection means for selecting an actual candidate n-cell having the most advantageous evaluation value among those that have not led to an expansion index, for therefrom generating a next actual expansion index, and repeat control means for repeatedly activating said expansion means, said evaluation means and said selection means until the other end of said route is reached, and backtracking means activated by said repeat control means for backtracking a linked set of candidates then starting from the n-cell containing said other end until said one end is reached, said linked set constituting said route.